ASN.1 ECN has been an ISO standard thing for a while. ECN lets you add representation information to the ASN.1 schema, which sounds roughly DFDL-like. So now with DFDL being an ISO standard the obvious thing arises to compare/contrast them. So I did a quick exercise in that direction. An AI (with my help) created an equivalent ASN.1 Schema + ECN from the FakeTDL format specification text *document *on github. (FakeTDL is a small example of a fictitious military tactical data link on github DFDLSchemas) This PR exhibits that ASN.1 and ECN code and does some comparison. They’re not particularly equivalent – some limitations of ECN become apparent even in this small example. https://github.com/DFDLSchemas/faketdl/pull/12/files This is the chatGPT5 session I used to create the example (fairly long) https://chatgpt.com/share/68dd112a-3140-800f-ab7c-c0d043c0460a I asked it a bunch more things about ASN.1 ECN that go beyond just this example. By the end of this it was speculating too much, and confusing some concepts, but overall this was quite useful. Mike Beckerle Apache Daffodil PMC | daffodil.apache.org OGF DFDL Workgroup Co-Chair | www.ogf.org/ogf/doku.php/standards/dfdl/dfdl Owl Cyber Defense | www.owlcyberdefense.com